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This comprehensive guide delves into the intricate process of mitosis, exploring the phases such as Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis. Learn about chromosome alignment, spindle fibers, nuclear division, and more. Discover the significance of mitosis in creating identical daughter cells and maintaining chromosome numbers. Test your knowledge with a quiz on mitosis concepts. Follow a step-by-step explanation with visuals at iknow.net/cell_div_education.html.
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Cells divide during the mitotic phase Section 9.3
Interphase • Cell prepares for division by: • replicating DNA and organelles • increasing cell size
Interphase Cont. • G1 (Gap) Phase: * Growth-the cell grows in size. • S (Synthesis) Phase of Cell Cycle:* The cell duplicates its chromosomes and cellular contents.* The chromosomes are in the form of chromatin (long and stringy material) • G2 (Gap) Phase of the Cell Cycle:* The cell prepares the enzymes and machinery for mitosis.
Prophase • Cell prepares for nuclear division by: • condensing DNA into movable packages called chromosomes • DNA wrapped around histone proteins Early Prophase Late Prophase
Prophase Cont. Early Prophase • During early prophase, the chromosomes condense, making them distinguishable when using a light microscope. • The nuclear envelope disperses. Late Prophase • During late prophase, the nucleoli disappear and the mitotic spindle apparatus assembles. • The mitotic spindle will consist of microtubules that extend from pole to pole.
Metaphase • Cell prepares chromosomes for division by: • aligning chromosomes at cell equator • attaching spindle fibers from each new daughter cell pole to each chromosome at the centromere
Chromosomes divide: spindle fibers pull chromosomes apart one-half of each chromosome (chromatid) moves to a new daughter cell Anaphase Early Anaphase Late Anaphase
Cytoplasm divides: DNA decondenses and two nuclei form new cell wall (cell plate) appears between the two nuclei to form two new daughter cells The process of cytokinesis, where the cytoplasm is divided by cleavage, also starts sometime in late anaphase and continues through telophase Telophase
The final steps are : completion of the total formation of a membrane between each of the new daughter cells to yield two identical but separate new cells. Daughter Cells
SignificanceofMitosis • Mitosis results in exactly identical chromosomes in each daughter cell. • The number of chromosomes stays the same following mitosis: • a diploid cell produces diploid cells • a haploid cell produces haploid cells
Concept Check 9.3 • Describe a significant event that occurs in each of the four stages of mitosis. • Compare and contrast cytokinesis in animal and plant cells. • In what sense may prophase and telophase in mitosis be characterized as opposites?
Lets see Real Cells Divide • http://iknow.net/cell_div_education.html